Pectobacterium polaris

The causative agent of this disease is the Gram-negative bacterium Pectobacterium polaris, belonging to the Pectobacteriaceae family. It is a highly aggressive phytopathogenic microorganism known to cause severe soft rot in a wide range of vegetable crops. The bacterium secretes a potent mixture of enzymes, particularly pectate lyases, which degrade the cell walls of plants, resulting in the rapid maceration and collapse of the plant tissue.

The primary hosts for this pathogen include potatoes, various root vegetables, and several cruciferous crops. Pectobacterium polaris is known for its ability to persist in soil, on crop debris, and within infected seed tubers for extended periods. As its name implies, this species is particularly well-adapted to cooler climates, often causing significant issues in regions with temperate growing conditions.

Symptoms of the infection typically manifest as localized areas of soft, watery decay that spread rapidly throughout the tissue. In tubers and fleshy roots, this rot is often characterized by a creamy, mucilaginous texture and an offensive odor. Aerial symptoms on stems and leaves include sudden wilting and the appearance of dark, moist lesions that enlarge quickly under high-humidity conditions.

Environmental conditions play a critical role in the development of the disease. High soil moisture, rainy weather, and temperatures ranging from moderate to cool create the ideal environment for bacterial proliferation. Infection usually occurs through natural openings (lenticels) or wounds created by agricultural machinery, pests, or during harvesting, allowing the bacteria to enter and colonize healthy plant tissues.

The economic impact of Pectobacterium polaris is substantial, as it leads to high post-harvest losses and reduced marketability of fresh produce. Effective management requires an integrated approach, including the use of certified pathogen-free seeds, strict crop rotation practices, and minimizing mechanical damage during harvest. Maintaining proper storage conditions with adequate aeration and low humidity is essential to preventing mass spoilage.

• Sanitation of harvesting and processing equipment.
• Proper curing of tubers before long-term storage.
• Removal and destruction of infected crop debris.
• Use of resistant cultivars when available.